Hi
Welcome to HCM and thanks for your query.
Common causes are
1.
Hydrocele.
2. Hernia.
3.
Varicocele.
If not done already., a physical examination is a must by a surgeon/
urologist.
Till then you can try
1. Tight scrotal support.
2. Ice application over the painful area.
Wishing you good health
Regards
Dr GS.